In Galatians 5:13–15 Paul writes:

My brothers, you were called, as you know, to liberty, but be careful, or this liberty will provide an opening for self indulgence. Serve one another, rather, in works of love, since the whole of the Law is summarized in a single command: Love your neighbor as yourself.

So, the issue is that the believer’s path may actually lead them astray and so may lead to a Kingdom of warring factions like those Paul was dealing with on earth (Super-apostles, Cephas, Apollos, etc). 

The Jewish ethics of the Mosaic Covenant Theology recalled that just as God had delivered his people from Egypt and from so many empires so the people should keep his law which he gave them. But now Paul is explaining the new law of agape as based on the Davidic Promise Theology rather than the Mosaic Covenant Theology and he emphasized the renewal of the Davidic promise in that the promise is no longer so much concerned with the renewal of the promised land and a Jewish nation but for blessing for all persons of the earth. The emphasis is on serving others. All five kinds of Greek ethics were also types of self realization ethics which are here transformed into an ethics of suffering and service for others. Being called to live in the incarnated, crucified resurrected Body of Christ means that we are now to love all others humans persons as we love our self for now each and every single individual person has a unique worth as a member of the Body of Christ. Even though Christ has redeemed us the call must go out to each person so that he or she can begin to serve the neighbor rather than being caught up in self-indulgence. This new notion of the neighbor as including every human person takes us beyond the limits of living according to the law of the flesh.  Goicoechea, David. Agape and Personhood: with Kierkegaard, Mother, and Paul (A Logic of Reconciliation from the Shamans to Today) (Postmodern Ethics Book 2) (pp. 199-200). Pickwick Publications, an Imprint of Wipf and Stock Publishers. Kindle Edition.

Goicoechea argued, as Nietzsche did before him, Paul grafted his philosophy/theology onto a Stoic trunk:

At Tarsus, where Paul grew up, there was a Stoic school and being a Roman citizen for him meant knowing and practicing the Greco- Roman Stoic philosophy with its universal law for all reasoning humans which Paul preferred to the Mosaic Law after his conversion. The Stoics explained how by cultivating apathy we can be freed from a network of concupiscible and irascible passions and freed for a life of reasoned calm and tranquility. That sort of tranquility could bring about self realization and the great Roman Peace. In a Stoic form but with a revolutionary new material list Paul writes at Galatians 5:19–23 When self-indulgence is at work the results are obvious: fornication, gross indecency and sexual irresponsibility; idolatry and sorcery; feuds and wrangling; jealousy, bad temper and quarrels; disagreements, factions, envy; drunkenness, orgies and similar things . . . What the Spirit brings is very different: love, joy, peace, patience, kindness, goodness, trustfulness, gentleness and self-control . . . you cannot belong to Christ Jesus unless you crucify all self-indulgent passion and desires. So Paul does state his new ethics in the Stoic form of becoming free from vice and free for virtues but the Stoic would still have a self-centered ethics of self-realization whereas the suffering servant will love especially the enemy with this new agape.  Goicoechea, David. Agape and Personhood: with Kierkegaard, Mother, and Paul (A Logic of Reconciliation from the Shamans to Today) (Postmodern Ethics Book 2) (pp. 200-201). Pickwick Publications, an Imprint of Wipf and Stock Publishers. Kindle Edition.

Paul’s love of others is a universal love of children as all people are children of God, not just the Jews.

Plato in his Symposium and Phaedrus explained his ethics in terms of a growth in a more and more excellent eros that could let the soul and the city state be liberated through recollection. Aristotle continued on with the same four cardinal virtues but explained them in terms of an Apollonian friendship rather than in the Platonic terms of a Dionysian eros. Aristotle’s ethics too is a self-realization ethics in which the virtues are means to the end of one’s own happiness and also a happy and healthy city state which persons who practice the four moral virtues and the five intellectual virtues can attain by being good political animals for their highest good. Paul’s ethics of agape with its three theological virtues as the primary structures of the new Christian attitude radically differs from both the eros ethics of Plato and the Philia ethics of Aristotle in aiming at the joy and peace of reconciliation for all the creatures of the earth.  For Plato and Aristotle there were still the Greeks and the Barbarians just as for the Jews there were Jews and Gentiles. Paul sees Jesus as going beyond this self-realization ethics of us and them to a new ethics of brotherly love of all humans. Now the Stoics did think along those lines in that they thought that the reason that all humans share in common is the basis for a brotherhood of man. But their universality of a brotherhood of all reasoning beings still depended on power and setting up an empire of Caesar’s power that could enforce peace… The Stoics thought of the long chain of negative passions as colliding with the long chain of positive passions and each of the passions had a mechanism of self interested desire within it. If we cultivated detachment from a small self interested desire through apathy we could build up the good of the cosmopolitan whole.  Given its universalism you can see why of the Greek ethical views Paul would build on Stoicism in thinking of his Christian ethics.  Goicoechea, David. Agape and Personhood: with Kierkegaard, Mother, and Paul (A Logic of Reconciliation from the Shamans to Today) (Postmodern Ethics Book 2) (p. 203). Pickwick Publications, an Imprint of Wipf and Stock Publishers. Kindle Edition.

The Greeks didn’t teach suffering as Paul did for the other as part of the body of Christ as his body suffered. 

Thus in their ethical and political thinking the Greeks would always put themselves as first and see Barbarians as inferior. So also the Jews as the chosen people of God would always because of their history of being subjugated by empires, see others as natural enemies rather than as members of Christ’s Body. So Paul’s new ethics of the agapeic imperative which says: “Love your neighbor as yourself” and included all humans as neighbors, especially our enemies and persecutors, turns the ethics of the territorial imperative of the natural law completely upside down.  Goicoechea, David. Agape and Personhood: with Kierkegaard, Mother, and Paul (A Logic of Reconciliation from the Shamans to Today) (Postmodern Ethics Book 2) (p. 204). Pickwick Publications, an Imprint of Wipf and Stock Publishers. Kindle Edition.

It is the urgency of Paul in making others right in God’s eye with the eschaton underway that we can reconcile the equality of all people with the social reality of stratification.

Even though Paul’s ethics is revolutionary in his totally new approach to all humans being our neighbors whom we should love as ourselves and in his new belief in the equality of all persons be they Greek, Jew, female, male, master, or slave he was not an insurrectionist who wanted to fight the Roman State and its injustices. Because of his belief in an immanent second coming he thought Christ would come soon and bring about a new Kingdom of love, justice, and peace for everyone. So until then men and women should keep their traditional customs as should masters and slaves and Greeks and Jews. Jewish men could be circumcised but it was very important that Gentile men need not be. Women should still wear head covering in church and glorify men as men glorify God. A slave should go back to his master. Of course, we should all love each other as equals in the Body of Christ, but we should keep the old customs until Christ comes and establishes his new Kingdom.  Goicoechea, David. Agape and Personhood: with Kierkegaard, Mother, and Paul (A Logic of Reconciliation from the Shamans to Today) (Postmodern Ethics Book 2) (pp. 206-207). Pickwick Publications, an Imprint of Wipf and Stock Publishers. Kindle Edition.

The Greek world advocated taking care of your immediate circle, while Judaism advocated caring for all Israelites, even strangers.  Ehrman notes caring for your neighbor for Jesus was far more important than temple practices (Mark 12:33).  This is loving both those who beat you and those who beg from you. 

Jesus’s famous parable shows a different way. It is a Samaritan who exemplifies the law of loving one’s Jewish neighbor.18 The neighbor is anyone in need, even an archenemy. This is a universalized ethic, not focusing on assisting loved ones but hated ones. You won’t find a story like that in ancient Greek or Roman moral philosophy.  Ehrman, Bart D.. Love Thy Stranger: How the Teachings of Jesus Transformed the Moral Conscience of the West (p. 118). Simon & Schuster. Kindle Edition.

I agree generally here but as I often say there are exceptions, like Socrates offering the prayer of thanksgiving to Asclepius in the Phaedo for the poison and the impaled just man of the Republic.  Jesus notes my neighbor is anyone in need in the parable of the good Samaritan, and the story of sheep and goats is about all the nations of the world and what mattered was helping everyone in need, which glorified Christ.  This likely goes back to the historical Jesus, Ehrman says, because it says there is salvation aside from cross/resurrection theology. Ehrman argues cross atonement/resurrection theology was invented after Jesus died. Jesus was killed, but then some of his followers thought they saw him after his death, and concluded the death was not random but a sacrifice.